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Abstract:

The present invention discloses a liquid crystal slit grating and a
stereoscopic display device, the liquid crystal slit grating includes a
first grating substrate and a second grating substrate facing each other,
and a plurality of photo spacers supporting between the first grating
substrate and the second grating substrate; the stereoscopic display
device includes a display panel and said liquid crystal slit grating
which is parallel to each other. The liquid crystal slit grating of the
present invention provides conditions for accurately controlling effects
of the photo spacers on light transmittance or accurately controlling
crosstalk caused by the photo spacers. The stereoscopic display device of
the present invention provides conditions for improving 3D effect of
stereoscopic display device during three dimensionally displaying.

Claims:

1. A liquid crystal slit grating, including: a first grating substrate
and a second grating substrate facing each other, and a plurality of
photo spacers provided between the first grating substrate and the second
grating substrate; wherein, the plurality of photo spacers are only
provided in an opaque stripe area of the liquid crystal slit grating, or
the plurality of photo spacers are only provided in a transparent stripe
area of the liquid crystal slit grating, or the plurality of photo
spacers are only provided at junction of adjacent opaque stripe area and
transparent stripe area of the liquid crystal slit grating, or wherein,
one part of the plurality of photo spacers is provided in an opaque
stripe area of the liquid crystal slit grating, and the other part of the
plurality of photo spacers is provided at junction of adjacent opaque
stripe area and transparent stripe area of the liquid crystal slit
grating, or one part of the plurality of photo spacers is provided in a
transparent stripe area of the liquid crystal slit grating, and the other
part of the plurality of photo spacers is provided at junction of
adjacent opaque stripe area and transparent stripe area of the liquid
crystal slit grating.

2. The liquid crystal slit grating according to claim 1, wherein, a first
polarizer is provided on a surface of the first grating substrate
opposite to the second grating substrate, a second polarizer is provided
on a surface of the second grating substrate opposite to the first
grating substrate, and polarization directions of the first polarizer and
the second polarizer are perpendicular or parallel to each other.

3. The liquid crystal slit grating according to claim 2, wherein, the
polarization directions of the first polarizer and the second polarizer
are parallel to each other, and the plurality of photo spacers are only
provided in a transparent stripe area of the liquid crystal slit grating,
or wherein, the polarization directions of the first polarizer and the
second polarizer are perpendicular to each other, and the plurality of
photo spacers are only provided in an opaque stripe area of the liquid
crystal slit grating.

4. The liquid crystal slit grating according to claim 2, wherein, nematic
liquid crystal layer with twisted angle of 90 degree is provided between
the first grating substrate and the second grating substrate, the first
grating substrate includes a first substrate, a first electrode and a
first alignment layer are sequentially formed on a surface of the first
substrate facing the second grating substrate, and the first polarizer is
provided on a surface of the first substrate opposite to the second
grating substrate, the second grating substrate includes a second
substrate, a second electrode and a second alignment layer are
sequentially formed on a surface of the second substrate facing the first
grating substrate, and the second polarizer is provided on a surface of
the second substrate opposite to the first grating substrate, and the
plurality of photo spacers are provided between the first alignment layer
and the second alignment layer.

5. The liquid crystal slit grating according to claim 4, wherein, the
second electrode includes a plurality of first stripe electrodes in
parallel, the plurality of first stripe electrodes are provided on the
second substrate at intervals, and the second alignment layer covers the
first stripe electrodes and each interval area between the first stripe
electrodes.

6. The liquid crystal slit grating according to claim 5, wherein, one
portion of orthographic projection of every photo spacer on the second
substrate is located within orthographic projection of one of the
plurality of first stripe electrodes on the second substrate, and the
other portion of the orthographic projection of every photo spacer on the
second substrate is located within orthographic projection of the
interval areas on the second substrate, or wherein, the whole
orthographic projection of every photo spacer on the second substrate is
located with the orthographic projection of one of the plurality of first
stripe electrodes on the second substrate.

7. The liquid crystal slit grating according to claim 6, wherein, a half
of the orthographic projection of every photo spacer on the second
substrate is located within the orthographic projection of one of the
plurality of first stripe electrodes on the second substrate, and another
half of the orthographic projection of every photo spacer on the second
substrate is located within the orthographic projection of the interval
areas on the second substrate.

8. The liquid crystal slit grating according to claim 4, wherein, the
second electrode includes a plurality of first stripe electrodes and a
plurality of second electrodes which are alternately provided and
parallel to each other, and the second alignment layer covers the first
stripe electrodes and the second stripe electrodes.

9. The liquid crystal slit grating according to claim 8, wherein, one
portion of orthographic projection of every photo spacer on the second
substrate is located within orthographic projection of one of the
plurality of first stripe electrodes on the second substrate, and the
other portion of the orthographic projection of every photo spacer on the
second substrate is located within orthographic projection of one of the
plurality of second stripe electrodes on the second substrate, or
wherein, the whole orthographic projection of every photo spacer on the
second substrate is located within the orthographic projection of one of
the plurality of first stripe electrodes on the second substrate, or
wherein, the whole orthographic projection of every photo spacer on the
second substrate is located within the orthographic projection of one of
the plurality of second stripe electrodes on the second substrate.

10. The liquid crystal slit grating according to claim 9, wherein, a half
of the orthographic projection of every photo spacer on the second
substrate is located within the orthographic projection of one of the
plurality of first stripe electrodes on the second substrate, and another
half of the orthographic projection of every photo spacer on the second
substrate is located within the orthographic projection of one of the
plurality of second stripe electrodes on the second substrate.

11. The liquid crystal slit grating according to claim 4, wherein, the
photo spacers are formed on the first alignment layer or on the second
alignment layer.

12. A stereoscopic display device, including a display panel and the
liquid crystal slit grating according to claim 1, wherein and the display
panel and the liquid crystal slit grating are provided in parallel.

13. The stereoscopic display device according to claim 12, wherein,
orthographic projection of every photo spacer of the liquid crystal slit
grating on the display panel is located within black matrix of the
display panel.

14. A stereoscopic display device, including a backlight; a liquid
crystal display panel; and a liquid crystal slit grating defined by claim
1, wherein, the liquid crystal slit grating and the liquid crystal
display panel are provided in parallel.

15. The stereoscopic display device according to claim 14, wherein, the
liquid crystal slit grating is provided at a light emitting side of the
liquid crystal display panel, and polarization direction of a second
polarizer of the liquid crystal slit grating is the same as that of an
upper polarizer of the liquid crystal display panel, or wherein, the
liquid crystal slit grating is provided between the liquid crystal
display panel and the backlight, and polarization direction of a first
polarizer of the liduid crystal slit grating is the same as that of a
lower polarizer of the liquid crystal display panel.

16. The stereoscopic display device according to claim 14, wherein,
orthographic projection of every photo spacer on the liquid crystal
display panel is located within black matrix of the liquid crystal
display panel.

17. The stereoscopic display device according to claim 15, wherein,
orthographic projection of every photo spacer on the liquid crystal
display panel is located within black matrix of the liquid crystal
display panel.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to technical field of stereoscopic
display, and particularly, to a liquid crystal slit grating and a
stereoscopic display device.

BACKGROUND OF THE INVENTION

[0002] An autostereoscopic display device refers to a display device with
which an image with stereoscopic effect can be observed through naked
eyes without wearing glasses. A slit grating type autostereoscopic
display device can alternately display pixels of a display panel by
column as left parallax images and right parallax images, and a grating
is provided in front of or behind the display panel in parallel. In a
basic structure as shown in FIG. 1, gratings 101 are parallel provided in
front of display panel 100. With the shielding effect of the gratings,
the left eye and right eye of an observer see left parallax images and
right parallax images displayed by pixels on a display panel,
respectively, and thus the observer obtains a visual stereoscopic display
image. The core component of a slit grating type autostereoscopic display
device is grating. In prior art, lens grating and slit grating are the
two main techniques. Wherein, slit grating can further be divided into
black-and-white stripe slit grating and liquid crystal slit grating.
Liquid crystal slit grating can be used not only for stereoscopic
display, but also for switching between two-dimensional display and
three-dimensional display.

[0003] Liquid crystal slit grating (i.e., a liquid crystal cell which can
form slit grating) includes twisted nematic liquid crystal mode
(abbreviated as TN mode) liquid crystal slit grating, advanced super
dimension switch (abbreviated as ADSDS mode) liquid crystal slit grating,
and the like. Wherein, TN mode liquid crystal slit grating is a liquid
crystal slit grating whose liquid crystal molecular forms a nematic
liquid crystal layer with twisted angle of 90 degree, and ADSDS mode
liquid crystal slit grating is a liquid crystal slit grating of which all
oriented liquid crystal molecular between and right above the slit
electrodes in a liquid crystal cell can be rotated through multiple
dimension electric field, and the multiple dimension electric filed
consists of the electric field generated by the edges of the slit
electrodes in the same plane and the electric field generated between a
slit electrode layer and a plate electrode layer.

[0004] As shown in FIG. 2, an existing TN mode liquid crystal slit grating
200 includes a first grating substrate and a second grating substrate.
Nematic liquid crystal layer 230 with twisted angle of 90 degree is
provided between the first grating substrate and the second grating
substrate. The first grating substrate includes a first polarizer 213, a
first substrate 210, a first electrode 211 covering the first substrate
210 and a first alignment layer 212 covering the first electrode 211. The
second grating substrate includes a second polarizer 223, a second
substrate 220, a second electrode 221 including a plurality of stripe
electrodes parallel to each other and a second alignment layer 222
covering each stripe electrode and interval areas between the stripe
electrodes.

[0005] In a case where the polarization directions of the first polarizer
213 and the second polarizer 223 are perpendicular to each other (i.e.,
the liquid crystal slit grating 200 is normally white mode), when there
is no potential difference between the first electrode 211 and the second
electrode 221, the nematic liquid crystal layer 230 provided between the
first grating substrate and the second grating substrate twists the
polarization direction of light by 90 degree, and thus light can pass
through the first polarizer 213 and the second polarizer 223. In other
words, when there is no potential difference between the first electrode
211 and the second electrode 221, the liquid crystal slit grating 200
wholly is transparent, and thus can be used for two-dimensional display.
On the other hand, when an operating potential difference exists between
the first electrode 211 and the second electrode 221, the potential
difference cause the nematic liquid crystal layer 230 located between
each stripe electrode of the second electrode 221 and the first electrode
211 not to twist the polarization direction of light by 90 degree, thus
the liquid crystal slit grating 200 displays black stripes at the
position of each stripe electrode, and transparent white stripes are
formed between adjacent black stripes. A plurality of black stripes form
opaque stripe area, and a plurality of white stripes form transparent
stripe area. Consequently, the liquid crystal slit grating 200 becomes a
slit grating with black stripes and white stripes at intervals, and can
realize three-dimensional display working with a display panel.

[0006] In a case where the polarization directions of the first polarizer
213 and the second polarizer 223 are parallel to each other (i.e., the
liquid crystal slit grating 200 is normally black mode), when there is no
potential difference between the first electrode 211 and the second
electrode 221, the nematic liquid crystal layer 230 provided between the
first grating substrate and the second grating substrate twists the
polarization direction of light by 90 degree, and thus the light cannot
pass the second polarizer 223 after passing the first polarizer 213. In
other words, when there is no potential difference between the first
electrode 211 and the second electrode 221, the liquid crystal slit
grating 200 wholly is opaque. On the other hand, when an operating
potential difference exists between the first electrode 211 and the
second electrode 221, the operating potential difference cause the
nematic liquid crystal layer 230 located between each stripe electrode of
the second electrode 221 and the first electrode 211 not to twist the
polarization direction of light by 90 degree any longer, thus the liquid
crystal slit grating 200 displays white stripes at the position of each
stripe electrode, and opaque black stripes are formed between adjacent
white stripes. A plurality of black stripes form opaque stripe area, and
a plurality of white stripes form transparent stripe area. Consequently,
the liquid crystal slit grating 200 becomes a slit grating with spaced
black stripes and white stripes, and can realize three-dimensional
display working with a display panel.

[0007] In prior art, TN mode liquid crystal slit grating mostly uses ball
spacers to support the first grating substrate and the second grating
substrate. As ball spacers are disposed by way of spraying, a lot of ball
spacers are sprayed in opaque stripe area and a lot of ball spacers are
sprayed in transparent stripe area at the same time, and the location of
a ball spacer cannot be accurately controlled. A ball spacer is isotropic
and does not twist the polarization direction of light. For liquid
crystal slit grating in normally white mode (i.e., the polarization
directions of the first polarizer 213 and the second polarizer 223 are
perpendicular to each other), the ball spacers located in the transparent
stripe area may form black dots in the transparent stripe area, and thus
affecting light transmittance. Therefore, for liquid crystal slit grating
in normally white mode, the formation manner of the ball spacers will
cause that the location of each ball spacer cannot be accurately
controlled, and further the effect of the ball spacers on light
transmittance cannot be accurately controlled. On the other hand, for
liquid crystal slit grating in normally black mode (i.e., the
polarization directions of the first polarizer 213 and the second
polarizer 223 are parallel to each other), the ball spacers located in
the opaque stripe area may form white dots in the opaque stripe area, and
thus being displayed as light leak and causing crosstalk, as shown in
FIG. 3. Therefore, for liquid crystal slit grating in normally black
mode, the formation manner of the ball spacers will cause that the
locations of ball spacers cannot be accurately controlled, and further
crosstalk caused by the ball spacers cannot be accurately controlled.

[0008] The above problems exist not only in a TN mode liquid crystal slit
grating, but also in a liquid crystal slit grating of other mode, such as
a ADSDS mode liquid crystal slit grating.

SUMMARY OF THE INVENTION

[0009] The present invention provides a liquid crystal slit grating and a
stereoscopic display device. The liquid crystal slit grating according to
the present invention can accurately control effect of spacers on light
transmittance or accurately control crosstalk caused by spacers. The
stereoscopic display device according to the present invention can
improve three dimensional effect of the stereoscopic display device
during three dimensionally displaying.

[0010] According to one aspect of the present invention, a liquid crystal
slit grating is provided, which includes: a first grating substrate and a
second grating substrate facing each other, and a plurality of photo
spacers supporting between the first grating substrate and the second
grating substrate.

[0011] Preferably, a first polarizer may be provided on a surface of the
first grating substrate opposite to the second grating substrate, a
second polarizer may be provided on a surface of the second grating
substrate opposite to the first grating substrate, and directions of the
first polarizer and the second polarizer are perpendicular or parallel to
each other.

[0012] When the polarization directions of the first polarizer and the
second polarizer are parallel to each other, the plurality of photo
spacers may be provided in a transparent stripe area of the liquid
crystal slit grating.

[0013] When the polarization directions of the first polarizer and the
second polarizer are perpendicular to each other, the plurality of photo
spacers may be provided in an opaque stripe area of the liquid crystal
slit grating.

[0014] Preferably, nematic liquid crystal layer with twisted angle of 90
degree may be provided between the first grating substrate and the second
grating substrate. The first grating substrate may include a first
substrate, a first electrode and a first alignment layer are sequentially
formed on a surface of the first substrate facing the second grating
substrate, and the first polarizer may be provided on a surface of the
first substrate opposite to the second grating substrate. The second
grating substrate may include a second substrate, a second electrode and
a second alignment layer are sequentially formed on a surface of the
second substrate facing the first grating substrate, and the second
polarizer may be provided on a surface of the second substrate opposite
to the first grating substrate. The plurality of photo spacers may be
provided between the first alignment layer and the second alignment
layer.

[0015] According to an embodiment of the present invention, the second
electrode may include a plurality of first stripe electrodes in parallel,
the plurality of first stripe electrodes may be provided on the second
substrate at intervals, and the second alignment layer may cover the
first stripe electrodes and each interval area between the first stripe
electrodes.

[0016] According to another embodiment of the present invention, the
second electrode may include a plurality of first stripe electrodes and a
plurality of second electrodes which are alternately provided and
parallel to each other, and the second alignment layer may cover the
first stripe electrodes and the second stripe electrodes.

[0017] In a case where the second electrode includes a plurality of first
stripe electrodes in parallel, one portion of orthographic projection of
every photo spacer on the second substrate may be located within
orthographic projection of one of the plurality of first stripe
electrodes on the second substrate, and the other portion of the
orthographic projection of every photo spacer on the second substrate may
be located within orthographic projection of the interval areas on the
second substrate.

[0018] Preferably, half of the orthographic projection of every photo
spacer on the second substrate may be located within the orthographic
projection of one of the plurality of first stripe electrodes on the
second substrate, and another half of the orthographic projection of
every photo spacer on the second substrate may be located within the
orthographic projection of the interval areas on the second substrate.

[0019] Alternatively, the orthographic projection of every photo spacer on
the second substrate may be located within the orthographic projection of
one of the plurality of first stripe electrodes on the second substrate

[0020] In a case where the second electrode includes a plurality of first
stripe electrodes and a plurality of second electrodes which are
alternately provided and parallel to each other, one portion of
orthographic projection of every photo spacer on the second substrate may
be located within orthographic projection of one of the plurality of
first stripe electrodes on the second substrate, and the other portion of
the orthographic projection of every photo spacer on the second substrate
may be located within orthographic projection of one of the plurality of
second stripe electrodes on the second substrate.

[0021] Preferably, half of the orthographic projection of every photo
spacer on the second substrate may be located within the orthographic
projection of one of the plurality of first stripe electrodes on the
second substrate, and another half of the orthographic projection of
every photo spacer on the second substrate may be located within the
orthographic projection of one of the plurality of second stripe
electrodes on the second substrate.

[0022] Alternatively, the orthographic projection of every photo spacer on
the second substrate may be located within the orthographic projection of
one of the plurality of first stripe electrodes on the second substrate.
Alternatively, the orthographic projection of every photo spacer on the
second substrate may be located within the orthographic projection of one
of the plurality of second stripe electrodes on the second substrate.

[0023] The photo spacers may be formed on the first alignment layer or on
the second alignment layer.

[0024] According to another aspect of the present invention, a
stereoscopic display device is provided, which includes a display panel
and the liquid crystal slit grating according to the present invention,
and the display panel and the liquid crystal slit grating are provided in
parallel.

[0025] According to still another aspect of the present invention, a
stereoscopic display device is provided, which includes a backlight, a
liquid crystal display panel and the liquid crystal slit grating
according to the present invention, and the liquid crystal slit grating
and the liquid crystal display panel are provided in parallel.

[0026] The liquid crystal slit grating may be provided at a light emitting
side of the liquid crystal display panel, and polarization direction of
the second polarizer is the same as that of an upper polarizer of the
liquid crystal display panel.

[0027] Alternatively, the liquid crystal slit grating may be provided
between the liquid crystal display panel and the backlight, and
polarization direction of the first polarizer is the same as that of a
lower polarizer of the liquid crystal display panel.

[0028] Preferably, orthographic projection of every photo spacer on the
display panel (or the liquid crystal display panel) is located within
black matrix of the display panel (or the liquid crystal display panel).

[0029] The liquid crystal slit grating provided by the present invention
may accurately control the position of every photo spacer by using photo
spacers formed through mask, lithography process and the like, and thus
can accurately control impact of spacers on light transmittance or
accurately control crosstalk caused by spacers. The stereoscopic display
device provided by the present invention including the liquid crystal
slit grating according to the present invention, and accordingly can
improve three dimensional effect of the stereoscopic display device
during three dimensionally displaying.

[0032] FIG. 3 is a schematic diagram illustrating that in a case where an
existing TN mode liquid crystal slit grating is normally black mode, ball
spacers in an opaque stripe area form white dots in the opaque stripe
area;

[0033]FIG. 4 is a schematic diagram of a liquid crystal slit grating
according to an embodiment of the present invention;

[0034]FIG. 5 is a schematic diagram of a liquid crystal slit grating
according to another embodiment of the present invention;

[0035] FIG. 6 is a schematic diagram of a liquid crystal slit grating
according to another embodiment of the present invention;

[0036] FIG. 7 is a schematic diagram of a liquid crystal slit grating
according to another embodiment of the present invention;

[0037] FIG. 8 is a schematic diagram of a liquid crystal slit grating
according to another embodiment of the present invention; and

[0038] FIG. 9 is a schematic diagram of a stereoscopic display device
according to an embodiment of the present invention.

[0045] The embodiments of the present invention will be described clearly
and completely in conjunction with the accompanying drawings illustrating
the embodiments of the present invention below. However, the described
embodiments are illustrative and not restrictive. Based on the teaching
of the present invention, modifications and variations can be made to
each embodiment by the person skilled in the art in detail and formality,
and the present invention is intended to include all these modifications
and variations.

[0046]FIG. 4 is a schematic diagram of liquid crystal slit grating 200
according to an embodiment of the present invention. As shown in FIG. 4,
the liquid crystal slit grating 200 may include a first grating substrate
and a second grating substrate facing each other, and further include a
plurality of photo spacers 240 provided between the first grating
substrate and the second grating substrate. Nematic liquid crystal layer
230 with twisted angle of 90 degree may be provided between the first
grating substrate and the second grating substrate. The first grating
substrate may include a first substrate 210, and a first electrode 211
and a first alignment layer 212 are sequentially provided on a surface of
the first substrate 210 facing the second grating substrate. A first
polarizer 213 may be provided on a surface of the first substrate 210
opposite to the second grating substrate. The second grating substrate
may include a second substrate 220, and a second electrode 221 and a
second alignment layer 222 are sequentially provided on a surface of the
second substrate 220 facing the first grating substrate. A second
polarizer 223 may be provided on a surface of the second substrate 220
opposite to the first grating substrate. The plurality of photo spacers
240 may be provided between the first alignment layer 212 and the second
alignment layer 222.

[0047] The polarization directions of the first polarizer 213 and the
second polarizer 223 may be parallel to each other, and in this
situation, the plurality of photo spacers 240 may be provided in a
transparent stripe area of the liquid crystal slit grating 200.
Alternatively, the polarization directions of the first polarizer 213 and
the second polarizer 223 may be perpendicular to each other, and in this
situation, the plurality of photo spacers 240 may be provided in an
opaque stripe area of the liquid crystal slit grating 200.

[0048] According to the embodiment shown in FIG. 4, the second electrode
221 includes a plurality of first stripe electrodes parallel to each
other, the plurality of first stripe electrodes are provided on the
second substrate 220 at intervals, and the second alignment layer 222
covers each first stripe electrode and each interval area between the
first stripe electrodes. One portion of orthographic projection of every
photo spacer 240 on the second substrate 220 is located within the
orthographic projection of one of the plurality of first stripe
electrodes on the second substrate 220, and the other portion of the
orthographic projection of every photo spacer 240 on the second substrate
220 is located within the orthographic projection of the interval areas
on the second substrate 220. Preferably, half of the orthographic
projection of every photo spacer 240 on the second substrate 220 is
located within the orthographic projection of one of the plurality of
first stripe electrodes on the second substrate 220, and another half of
the orthographic projection of every photo spacer 240 on the second
substrate 220 is located within the orthographic projection of the
interval areas on the second substrate 220.

[0049] In a case where the polarization directions of the first polarizer
213 and the second polarizer 223 are perpendicular to each other (i.e.,
the liquid crystal slit grating 200 is normally white mode), when there
is operating potential difference existing between the first electrode
211 and the second electrode 221, this operating potential difference
causes the nematic liquid crystal layer 230 located between each first
stripe electrode of the second electrode 221 and the first electrode 211
not to twist the polarization direction of light by 90 degree any longer,
thus the liquid crystal slit grating 200 displays black stripes at the
position of each first stripe electrode, and white stripes which are
transparent are formed between adjacent black stripes. A plurality of
black stripes form opaque stripe area, and a plurality of white stripes
form transparent stripe area. In this case, the photo spacers 240 are
provided at junction areas of the opaque stripes and the transparent
stripes.

[0050] On the other hand, in a case where the polarization directions of
the first polarizer 213 and the second polarizer 223 are parallel to each
other (i.e., the liquid crystal slit grating 200 is normally black mode),
when there is operating potential difference existing between the first
electrode 211 and the second electrode 221, this operating potential
difference causes the nematic liquid crystal layer 230 located between
each first stripe electrode of the second electrode 221 and the first
electrode 211 not to twist the polarization direction of light by 90
degree any longer, thus the liquid crystal slit grating 200 displays
white stripes at the position of each first stripe electrode, and opaque
black stripes are formed between adjacent white stripes. A plurality of
black stripes form opaque stripe area, and a plurality of white stripes
form transparent stripe area. In this case, the photo spacers 240 are
still provided at junction areas of the opaque stripes and the
transparent stripes.

[0051] Therefore, according to the embodiment shown in FIG. 4, whether the
polarization directions of the first polarizer 213 and the second
polarizer 223 are perpendicular (i.e., normally white mode) or parallel
(i.e., normally black mode) to each other, the orthographic projection of
the photo spacers 240 in the transparent stripe area or the opaque strip
area is only a part of the orthographic projection of the photo spacers
240 (preferably, is a half of the orthographic projection of the photo
spacers 240). Therefore, for the liquid crystal slit grating 200 in
normally white mode, the formation manner of the photo spacers 240 can
effectively control the effect of the photo spacers 240 on light
transmittance. On the other hand, for the liquid crystal slit grating 200
in normally black mode, the formation manner of the photo spacers 240 can
preferably control the crosstalk caused by the photo spacers 240.

[0052] Particularly, the potential difference between each first stripe
electrode of the second electrode 221 and the first electrode 211 may
cause the display area corresponding to the edge of each first stripe
electrode to generate certain crosstalk, and the display area
corresponding to the edge of each photo spacer 240 may also generate
certain crosstalk. According to the embodiment shown in FIG. 4, the
crosstalk generated by the edges of the first stripe electrodes and the
crosstalk generated by the edges of the photo spacers 240 may
positionally overlap in part, and thus reducing the total area of the
crosstalk generated by the edges of the first stripe electrodes and the
crosstalk generated by the edges of the photo spacers 240.

[0053]FIG. 5 is a schematic diagram of a liquid crystal slit grating 200
according to another embodiment of the present invention. Compared to the
embodiment shown in FIG. 4, the position where each photo spacer is
formed is different. For purpose of clarity, below will focus on the
difference from the embodiment shown in FIG. 4, and the same parts will
be omitted.

[0054] As shown in FIG. 5, the orthographic projection of every photo
spacer 240 on the second substrate 220 is located within the orthographic
projection of one of the plurality of first stripe electrodes on the
second substrate 220.

[0055] In a case where the polarization directions of the first polarizer
213 and the second polarizer 223 are perpendicular to each other (i.e.,
the liquid crystal slit grating 200 is normally white mode), when there
is operating potential difference existing between the first electrode
211 and the second electrode 221, this operating potential difference
causes the nematic liquid crystal layer 230 located between each first
stripe electrode of the second electrode 221 and the first electrode 211
not to twist the polarization direction of light by 90 degree any longer,
thus the liquid crystal slit grating 200 displays black stripes at the
position of each first stripe electrode, and white stripes which are
transparent are formed between adjacent black stripes. A plurality of
black stripes form opaque stripe area, and a plurality of white stripes
form transparent stripe area. In this case, the photo spacers 240 are
provided in the opaque stripe area. For the liquid crystal slit grating
200 in normally white mode, the photo spacers 240 provided in the opaque
stripe area will not affect light transmittance.

[0056] On the other hand, in a case where the polarization directions of
the first polarizer 213 and the second polarizer 223 are parallel to each
other (i.e., the liquid crystal slit grating 200 is normally black mode),
when there is operating potential difference existing between the first
electrode 211 and the second electrode 221, this operating potential
difference causes the nematic liquid crystal layer 230 located between
each first stripe electrode of the second electrode 221 and the first
electrode 211 not to twist the polarization direction of light by 90
degree any longer, thus the liquid crystal slit grating 200 displays
white stripes at the position of each first stripe electrode, and opaque
black stripes are formed between adjacent white stripes. A plurality of
black stripes form opaque stripe area, and a plurality of white stripes
form transparent stripe area. In this case, the photo spacers 240 are
provided in the transparent stripe area. For the liquid crystal slit
grating 200 in normally black mode, the photo spacers 240 provided in the
transparent stripe area will not generate crosstalk.

[0057] FIG. 6 is a schematic diagram of a liquid crystal slit grating 200
according to still another embodiment of the present invention. Compared
to the embodiment shown in FIG. 4, the second electrode 221 includes a
plurality of first stripe electrodes and a plurality of second stripe
electrodes 221' which are provided alternately and parallel to each
other, and the second alignment layer 222 covers the first stripe
electrodes and the second stripe electrodes 221'. For purpose of clarity,
below will focus on the difference from the embodiment shown in FIG. 4,
and the same parts will be omitted.

[0058] According to the embodiment shown in FIG. 6, one part of the
orthographic projection of every photo spacer 240 on the second substrate
220 is located within the orthographic projection of one of the plurality
of first stripe electrodes on the second substrate 220, and the other
part of the orthographic projection of every photo spacer 240 on the
second substrate 220 is located within the orthographic projection of one
of the plurality of second stripe electrodes 221' on the second substrate
220. Preferably, a half of the orthographic projection of every photo
spacer 240 on the second substrate 220 is located within the orthographic
projection of one of the plurality of first stripe electrodes on the
second substrate 220, and another half of the orthographic projection of
every photo spacer 240 on the second substrate 220 is located within the
orthographic projection of one of the plurality of second stripe
electrodes 221' on the second substrate 220.

[0059] In a case where the polarization directions of the first polarizer
213 and the second polarizer 223 are perpendicular to each other (i.e.,
the liquid crystal slit grating 200 is normally white mode), when there
is operating potential difference existing between the first electrode
211 and each first stripe electrode of the second electrode 221 whereas
there is no operating potential difference existing between the first
electrode 211 and each second stripe electrode 221' of the second
electrode 221, the operating potential difference between the first
electrode 211 and each first stripe electrode will cause the nematic
liquid crystal layer 230 located between each first stripe electrode of
the second electrode 221 and the first electrode 211 not to twist the
polarization direction of light by 90 degree any longer, thus the liquid
crystal slit grating 200 displays black stripes at the position of each
first stripe electrode, and white stripes which are transparent are
formed between adjacent black stripes. Alternatively, when there is
operating potential difference existing between the first electrode 211
and each second stripe electrode 221' of the second electrode 221 whereas
there is no operating potential difference existing between the first
electrode 211 and each first stripe electrode of the second electrode
221, the operating potential difference between the first electrode 211
and each second stripe electrode 221' will cause the nematic liquid
crystal layer 230 located between each second stripe electrode 221' of
the second electrode 221 and the first electrode 211 not to twist the
polarization direction of light by 90 degree any longer, thus the liquid
crystal slit grating 200 displays black stripes at the position of each
second stripe electrode 221', and white stripes which are transparent are
formed between adjacent black stripes. In any event, a plurality of black
stripes form opaque stripe area, and a plurality of white stripes form
transparent stripe area. In this case, the photo spacers 240 are provided
at the junction areas of the opaque stripes and the transparent stripes.

[0060] On the other hand, in a case where the polarization directions of
the first polarizer 213 and the second polarizer 223 are parallel to each
other (i.e., the liquid crystal slit grating 200 is normally black mode),
when there is operating potential difference existing between the first
electrode 211 and each first stripe electrode of the second electrode 221
whereas there is no operating potential difference existing between the
first electrode 211 and each second stripe electrode 221' of the second
electrode 221, the operating potential difference between the first
electrode 211 and each first stripe electrode will cause the nematic
liquid crystal layer 230 located between each first stripe electrode of
the second electrode 221 and the first electrode 211 not to twist the
polarization direction of light by 90 degree any longer, thus the liquid
crystal slit grating 200 displays white stripes at the position of each
first stripe electrode, and opaque black stripes are formed between
adjacent white stripes. Alternatively, when there is operating potential
difference existing between the first electrode 211 and each second
stripe electrode 221' of the second electrode 221 whereas there is no
operating potential difference existing between the first electrode 211
and each first stripe electrode of the second electrode 221, the
operating potential difference between the first electrode 211 and each
second stripe electrode 221' will cause the nematic liquid crystal layer
230 located between each second stripe electrode 221' of the second
electrode 221 and the first electrode 211 not to twist the polarization
direction of light by 90 degree any longer, thus the liquid crystal slit
grating 200 displays white stripes at the position of each second stripe
electrode 221', and opaque black stripes are formed between adjacent
white stripes. In any event, a plurality of black stripes form opaque
stripe area, and a plurality of white stripes form transparent stripe
area. In this case, the photo spacers 240 are still provided at the
junction areas of the opaque stripes and the transparent stripes.

[0061] Therefore, according to the embodiment shown in FIG. 6, whether the
polarization directions of the first polarizer 213 and the second
polarizer 223 are perpendicular (i.e., normally white mode) or parallel
(i.e., normally black mode) to each other, and whether there are
operating potential difference existing between the first electrode 211
and each first stripe electrode or between the first electrode 211 and
each second stripe electrode 221', the orthographic projection of the
photo spacers 240 in the transparent stripe area or the opaque strip area
is only a part of the orthographic projection of the photo spacers 240
(preferably, is a half of the orthographic projection of the photo
spacers 240). Therefore, for the liquid crystal slit grating 200 in
normally white mode, the formation manner of the photo spacers 240 can
effectively control the effect of the photo spacers 240 on light
transmittance. On the other hand, for the liquid crystal slit grating 200
in normally black mode, the formation manner of the photo spacers 240 can
preferably control the crosstalk caused by the photo spacers 240.

[0062] Particularly, the potential difference between each first stripe
electrode (or second stripe electrode 221') of the second electrode 221
and the first electrode 211 may cause the display area corresponding to
the edge of each first stripe electrode (or second stripe electrode 221')
to generate certain crosstalk, and the display area corresponding to the
edge of each photo spacer 240 may also generate certain crosstalk.
According to the embodiment shown in FIG. 6, the crosstalk generated by
the edges of the first stripe electrodes (or the second stripe electrodes
221') and the crosstalk generated by the edges of the photo spacers 240
may positionally overlap in part, and thus reducing the total area of the
crosstalk generated by the edges of the first stripe electrodes (or the
second stripe electrodes 221') and the crosstalk generated by the edges
of the photo spacers 240.

[0063] FIGS. 7 and 8 are schematic diagrams of liquid crystal slit
gratings 200 according to other embodiments of the present invention.
Compared to the embodiment shown in FIG. 6, the position where each photo
spacer is formed is different. For purpose of clarity, below will focus
on the difference from the embodiment shown in FIG. 6, and the same parts
will be omitted.

[0064] As shown in FIG. 7, the orthographic projection of every photo
spacer 240 on the second substrate 220 is located within the orthographic
projection of one of the plurality of first stripe electrodes on the
second substrate 220.

[0065] Alternatively, as shown in FIG. 8, the orthographic projection of
every photo spacer 240 on the second substrate 220 is located within the
orthographic projection of one of the plurality of second stripe
electrodes 221' on the second substrate 220.

[0066] In a case where there is operating potential difference existing
between the first electrode 211 and each first stripe electrode of the
second electrode 221 (the embodiment shown in FIG. 7) or in a case where
there is operating potential difference existing between the first
electrode 211 and each second stripe electrode 221' of the second
electrode 221 (the embodiment shown in FIG. 8), respectively, the
technical effects described according to FIG. 5 can be obtained, and the
detailed description thereof is thus omitted herein.

[0067] The photo spacers 240 may be formed on the first alignment layer
212 or on the second alignment layer 222. Preferably, the photo spacers
240 may be formed on the second alignment layer 222, and thus avoiding
effects on position accuracy of the photo spacers 240 caused by position
errors when assembling the first substrate and the second substrate.

[0068] According to another aspect of the present invention, there is
provided a stereoscopic display device, including a display panel and the
liquid crystal slit grating according to the present invention, and the
liquid crystal slit grating and the display panel are provided in
parallel. The display panel may be any one of an electronic ink display
panel of electronic book, a plasma display panel, a liquid crystal
display panel and an organic light emitting diode display panel.

[0069] According to still another aspect of the present invention, there
is provided a stereoscopic display device, including backlight, liquid
crystal display panel and the liquid crystal slit grating according to
the present invention, and the liquid crystal slit grating and the liquid
crystal display panel are provided in parallel. The liquid crystal slit
grating may be provided at a light emitting side of the liquid crystal
display panel, and polarization direction of the second polarizer of the
liquid crystal slit grating is the same as that of an upper polarizer on
the liquid crystal display panel. Alternatively, the liquid crystal slit
grating may be provided between the liquid crystal display panel and the
backlight, and polarization direction of the first polarizer of the
liquid crystal slit grating is the same as that of a lower polarizer on
the liquid crystal display panel.

[0070] FIG. 9 is a schematic diagram of a stereoscopic display device
according to an embodiment of the present invention. As shown in FIG. 9,
the orthographic projection of every photo spacer 240 of the liquid
crystal slit grating on the display panel is located within black matrix
110 of the display panel.

[0071] Every photo spacer of the liquid crystal slit grating will cause
disordered alignment of the surrounding liquid crystal thereof, and the
black matrix of the display panel will block emitted light. When the
orthographic projection of every photo spacer of the liquid crystal slit
grating on the display panel is located within the black matrix of the
display panel, there is no light around the photo spacers of the liquid
crystal slit grating, and thus reducing crosstalk caused by disordered
alignment of the liquid crystal surrounding the photo spacers.

[0072] Although each embodiment of the present invention has been
described in detail with reference to the drawings, the person skilled in
the art should understand that various modifications and variations can
be made to each embodiment of the present invention in detail and
formality without departing from the scope and spirit of the present
invention, and the present invention is intend to include all these
modifications and variations.